1. Field of the Invention
This invention relates to a film cartridge loading mechanism for a photographic camera which uses a film cartridge having a film exit slit and a light-shielding shutter member for opening and shutting the film exit slit.
2. Description of the Related Art
Recently there has been proposed a novel film cartridge in which a roll film is entirely rolled to its leading end around a spool in a cartridge body having a film exit slit and a light-shielding shutter member for opening and shutting the film exit slit. In such a film cartridge, when the film exit slit is shut, the roll film is entirely rolled around a spool to its leading end and held in a light-tight fashion and the roll film is fed out of the cartridge body and rewound into the cartridge body with the film exit slit opened.
Further we have proposed a photographic camera which uses such a novel film cartridge, for instance, in Japanese Unexamined Patent Publication No. 6(1994)-99909. The photographic camera is provided with a cartridge chamber in which the novel film cartridge is loaded, a chamber lid which opens and shuts an entrance opening to the cartridge chamber, a spool drive member which is engaged with the spool of the film cartridge loaded in the cartridge chamber and rotates the spool to feed out and rewind the film from and into the cartridge body, and a shutter opening member which is engaged with the light-shielding shutter member of the film cartridge and opens and shuts the film exit slit.
The camera and the film cartridge of these types are advantageous in that film loading is facilitated.
In the novel film cartridge, there is provided a lock member which prevents accidental opening of the light shielding shutter member when the film cartridge is handled outside the camera body. The lock member locks the rotary shaft of the shutter member to prevent rotation of the shutter member about the rotary shaft and releases the rotary shaft when an end of the rotary shaft of the shutter member is brought into engagement with the shutter opening member of the camera and the shutter opening member is brought into contact with the lock member.
In such a camera, the shutter member is released when the film cartridge loaded in the cartridge chamber is pushed inward and the shutter opening member deep in the cartridge chamber is brought into contact with the lock member pushed by the film cartridge. However when the chamber lid is shut with the film cartridge not loaded home in the cartridge chamber, the lock member sometimes cannot be correctly actuated and opening the light-shielding shutter member of the film cartridge becomes impossible.
However if the film cartridge is kept pushed with a large force in order to avoid such a problem, function of the novel film cartridge cannot be fully used.